JP7504242B1 - Shaft coupling and manufacturing method thereof - Google Patents

Abstract

[Problem] To easily realize a shaft coupling having an elastic member interposed between a pair of hubs. [Solution] A shaft coupling (1) includes a pair of metal hubs (3A, 3B) and an element (4) arranged between the hubs (3A, 3B) at a predetermined interval from each of the hubs (3A, 3B), the element (4) including a plurality of metal insert members (21A-21D) each having a pair of end faces (27, 28) and a peripheral surface (29) and fixed to the hubs (3A, 3B) by a fastener (41), and an elastomer elastic member (22) provided to cover at least a portion of the peripheral surface (29) of each of the insert members (21A-21D) so as to be integral with the insert members (21A-21D), the insert members (21A-21D) including a first insert member (21A, 21C) fixed to only one of the hubs (3A, 3B) and a second insert member (21B, 21D) fixed to only the other of the hubs (3A, 3B). [Selected figure] Figure 2

Description

The present invention relates to a shaft coupling that connects two shafts and a method for manufacturing the same.

A known shaft coupling connects the drive shaft of a control motor and the driven shaft on the load side, and includes a pair of hubs attached to the drive shaft and the driven shaft, respectively, and an elastic member made of a urethane resin composition interposed between the hubs (see Patent Document 1). With this shaft coupling, by interposing an elastic body made of a urethane resin composition between a pair of hubs made of aluminum or stainless steel, more stable vibration damping characteristics can be obtained compared to when a metal bellows or ring leaf spring is interposed between the hubs.

A method for manufacturing a shaft coupling with such an elastic member is known that includes the steps of manufacturing a pair of hub intermediates, inserting both intermediates into the insert chamber of a mold and, with the positioning projections or positioning holes formed on the outer end faces of both intermediates engaged, injecting an elastic material into the space formed between the opposing inner end faces of both intermediates to form an elastic member, removing the positioning projections or positioning holes of both intermediates after releasing the shaft coupling from the mold, and forming a connecting hole in the center of both intermediates (see Patent Document 2).

JP 2002-327774 A JP 2008-241029 A

In the conventional technology described in Patent Document 2, after the shaft coupling is released from the mold, the pair of hubs are integrated by the elastic member, and the steps of removing the positioning protrusions or positioning holes of both intermediate bodies and forming a connecting hole in the center of both intermediate bodies are further carried out.

In other words, in the above-mentioned conventional technology, in order to obtain a configuration in which an elastic member is interposed between a pair of hubs, machining (e.g., forming the shaft hole) that requires high precision must be performed while the pair of hubs are integrated with the elastic member (i.e., while the shaft coupling is assembled), which complicates the manufacturing process of the shaft coupling.

In view of the above background, the present invention aims to provide a shaft coupling and a manufacturing method thereof that can easily realize a configuration in which an elastic member is interposed between a pair of hubs.

In order to solve the above problem, one aspect of the present invention includes a pair of metal hubs (3A, 3B) having shaft holes (10A, 10B) into which two shafts (2A, 2B) are fitted, and an element (4) arranged between the pair of hubs at a predetermined interval from each of the hubs, each of which has a pair of end faces (27, 28) arranged to face each of the hubs and a peripheral surface (29) connected to the periphery of each end face, and includes multiple metal insert members (21A-21D) each fixed to the pair of hubs by a fastener (41), and an elastomer elastic member (22) provided to cover at least a portion of the peripheral surface of each of the insert members so as to be integral with the multiple insert members, and the multiple insert members include a first insert member (21A, 21C) fixed only to one of the pair of hubs, and a second insert member (21B, 21D) fixed only to the other of the pair of hubs.

According to this aspect, since there is no need to perform highly accurate machining (e.g., forming the shaft hole) when the shaft coupling is assembled, a configuration in which an elastic member is interposed between a pair of hubs can be easily realized. Another advantage of this aspect is that it increases the degree of freedom in combining each hub with an element.

In the above aspect, the element may be annular, and the multiple insert members may be arranged at equal intervals in the circumferential direction of the element.

This aspect allows the element to rotate smoothly when rotating around the two axes.

In the above aspect, each of the insert members may be provided so as to have a fan-shaped outer shape when viewed in the axial direction.

According to this aspect, the force acting on each insert member when the two shafts rotate can be transmitted appropriately (i.e. evenly) to the elastic member.

In the above aspect, the elastic member may be provided so as to cover the entire peripheral surface of each of the insert members.

This embodiment improves the integrity of the insert member and the elastic member, allowing the element to rotate stably when the two shafts rotate.

In the above aspect, the pair of hubs and the element may be configured to have the same outer diameter when viewed in the axial direction.

In the above embodiment, each of the hubs may have a slot (14) around the shaft hole, and the shaft may be removably fixed by expanding or contracting the slot.

According to this embodiment, the shaft can be detachably attached to the shaft hole by expanding or contracting the slot.

In order to solve the above problem, one aspect of the present invention is a method for manufacturing the shaft coupling, which includes a molding process for insert molding the element so that the multiple insert members and the elastic member are integrated, and an assembly process for fixing the insert molded element to the pair of hubs with the fasteners.

According to this aspect, it is not necessary to perform machining (e.g., forming a shaft hole) that requires high precision when the shaft coupling is assembled, so a configuration in which an elastic member is interposed between a pair of hubs can be easily realized without complicating the manufacturing process. In addition, according to this aspect, since the element can be completed independently of the hub, there is also the advantage that the time required to manufacture the shaft coupling can be shortened.

In the above aspect, each of the insert members may be tapered toward one or the other axial side.

This aspect makes it easier to remove the insert member from the mold after insert molding to form the elastic member around the insert member.

According to the above aspects, the shaft coupling and its manufacturing method can easily realize a configuration in which an elastic member is interposed between a pair of hubs.

FIG. 1 is a perspective view of a shaft coupling according to an embodiment; FIG. 1 is an exploded perspective view of a shaft coupling according to an embodiment; FIG. 1 is a perspective view of an element according to an embodiment; FIG. 1 is a longitudinal sectional view of a shaft coupling according to an embodiment of the present invention;

The shaft coupling and its manufacturing method according to an embodiment of the present invention will be described below with reference to the drawings. For ease of explanation, the up-down direction and the front-rear direction are defined as shown by the arrows in the drawings (Figure 1, etc.).

As shown in FIG. 1, the shaft coupling 1 is for connecting two rotatable shafts 2A and 2B, and includes a pair of metal clamp hubs 3A and 3B and an element 4 interposed between the clamp hubs 3A and 3B.

Shafts 2A and 2B each extend in the front-rear direction and are both arranged so that axis 5 is the center of rotation. The outer diameter of shaft 2B is set to be larger than the outer diameter of shaft 2A. However, shafts 2A and 2B may be provided to have the same outer diameter. For shafts 2A and 2B, for example, a drive shaft of a motor (not shown) and a shaft of a device driven by the motor (load side driven shaft) can be used. However, the form of the shaft to be connected to shaft coupling 1 is not limited to these.

As shown in FIG. 2, the clamp hubs 3A and 3B are generally annular, with shaft holes 10A and 10B formed in their centers. The shafts 2A and 2B are fitted and fixed in the shaft holes 10A and 10B, respectively. The diameter of the shaft hole 10B is set to be larger than the diameter of the shaft hole 10A so as to correspond to the outer diameter of the shafts 2A and 2B described above. The clamp hub 3B has the same configuration as the clamp hub 3A, except for the size of the shaft hole 10B. However, the clamp hub 3B is positioned in the opposite direction to the clamp hub 3A in the front-to-rear direction.

In the following, parts of clamp hubs 3A and 3B that have the same (or nearly the same) shape and function are given the same reference numerals. The same applies to the members (bolts, etc.) attached to clamp hubs 3A and 3B.

The clamp hub 3A has two through holes 11 extending in the front-rear direction (axial direction). The two through holes 11 are arranged in positions that are rotationally symmetrical to each other (i.e., positions that overlap when rotated 180 degrees around the axis 5). The clamp hub 3A also has two screw holes 12 extending in the front-rear direction. The two screw holes 12 are arranged in positions that are roughly rotationally symmetrical to the two through holes 11 (i.e., positions that roughly overlap when rotated 90 degrees around the axis 5).

In addition, when viewed from the front, the clamp hub 3A has a split groove 14 formed along the diameter direction and a slit 15 formed along the circumferential direction (or a direction perpendicular to the axis 5).

The split groove 14 opens to the front surface 17 and outer peripheral surface 18 of the clamp hub 3A. The split groove 14 is provided so as to cut the clamp hub 3A from its top partway in the diameter direction beyond the axial hole 10A (i.e., to a position where the clamp hub 3A is not completely cut). The rear end of the split groove 14 communicates with the slit 15.

The slit 15 opens into the outer peripheral surface 18 of the clamp hub 3A. The slit 15 is provided in the middle of the clamp hub 3A in the front-to-rear direction, cutting the clamp hub 3A from its top partway through the axial hole 10A in a direction perpendicular to the axis 5.

The clamp hub 3A also has a fastening screw hole 19 that extends in a direction perpendicular to the upper portion of the split groove 14.

The clamp hub 3A is made of a metal material such as aluminum or stainless steel. The configuration of the clamp hub 3B is the same as the configuration of the clamp hub 3A described above.

As shown in FIG. 3, the element 4 is generally annular, and has an axial hole 20 extending in the front-rear direction at its center. The axial hole 20 is provided coaxially with the axial holes 10A, 10B of the clamp hubs 3A, 3B (i.e., the axis of the element 4 coincides with the axis 5 of the clamp hubs 3A, 3B). The element 4 can also function as a spacer for the clamp hubs 3A, 3B. The axial hole 20 has generally the same diameter as the axial hole 10B of the clamp hub 3B. Furthermore, the element 4 is preferably provided to have the same outer diameter as the clamp hubs 3A, 3B when viewed in the axial direction.

The element 4 includes multiple (four in this case) metallic insert members 21A-21D and an elastomer elastic member 22 interposed between the insert members 21A-21D. The insert members 21A-21D are arranged at equal intervals (every 90 degrees in this case) around the circumference of the element 4 when viewed in the axial direction. The insert members 21A-21D can be made of a metallic material, similar to the clamp hubs 3A and 3B.

In the following, for insert members 21A-21D, parts that have the same or nearly the same shape or function will be given the same reference numerals.

The insert members 21A, 21C (an example of a first insert member) have the same configuration. When viewed in the axial direction, each insert member 21A, 21C is provided so as to have an approximately fan-shaped outer shape by extending in an arc shape along the circumferential direction of the element 4. As shown in FIG. 4, the circumferential center of each insert member 21A, 21C is provided with a plurality of bolt receiving holes 24 (here, 24) extending in the front-rear direction. Each bolt receiving hole 24 is provided coaxially with one through hole 11 and the other screw hole 12 in the corresponding clamp hub 3A, 3B (in FIG. 4, the screw hole 12 of clamp hub 3A and the through hole 11 of clamp hub 3B).

Each bolt receiving hole 24 includes a small diameter portion 24A that opens on the front surface 27 of each insert member 21A, 21C, and a large diameter portion 24B that is connected to the rear of the small diameter portion 24A and opens on the rear surface 28 of each insert member 21A, 21C. Each insert member 21A, 21C is tapered from the rear to the front (i.e., to one side) (i.e., the outer shape gradually becomes smaller from the rear surface 28 to the front surface 27). As a result, the thickness of the elastic member 22 that covers the outer peripheral surface portion 29A and the inner peripheral surface portion 29B of each insert member 21A, 21C gradually increases from the rear to the front, as shown in the cross-sectional view in FIG. 4.

In addition, the insert members 21B and 21D (an example of a second insert member) have the same configuration as the insert members 21A and 21C. However, the insert members 21B and 21D are arranged in the opposite direction to the insert members 21A and 21C in the front-to-rear direction. That is, in the bolt receiving holes 24 of the insert members 21B and 21D, the large diameter portion 24B opens to the front surface 27 of the insert members 21B and 21D, and the small diameter portion 24A opens to the rear surface 28 of the insert members 21B and 21D. Each insert member 21B and 21D is tapered from the front to the rear (i.e., the outer shape gradually becomes smaller from the front surface 27 to the rear surface 28) like the insert members 21A and 21C.

In addition, a pair of recesses 30 that are approximately circular when viewed in the axial direction are provided on the front surface 27 side of the insert members 21B and 21D so as to sandwich the large diameter portion 24B in the circumferential direction (the same is true for the rear surface 28 side of the insert members 21A and 21C).

The peripheral surface 29 of each insert member 21A-21D is continuous with the periphery of the front surface 27 and rear surface 28 (an example of an end surface). The peripheral surface 29 includes an outer peripheral surface portion 29A, an inner peripheral surface portion 29B, and a pair of flat surfaces 29C that connect the circumferential edges of the outer peripheral surface portion 29A and the inner peripheral surface portion 29B (see FIG. 3). However, the connection portions between the outer peripheral surface portion 29A and the inner peripheral surface portion 29B and the flat surfaces 29C form curved surfaces (with R-chamfered edges).

The elastic member 22 is provided so as to cover the entire peripheral surface 29 of the insert members 21A-21D so as to be integral with the insert members 21A-21D. That is, the elastic member 22 has a plurality of substantially fan-shaped through holes in which the insert members 21A-21D are respectively housed when viewed in the axial direction. On the other hand, the elastic member 22 exposes the front surface 27 and rear surface 28 of the insert members 21A-21D. However, it is sufficient that the elastic member 22 is provided so as to expose at least a part of the front surface 27 and rear surface 28 of the insert members 21A-21D (the openings of the small diameter portion 24A and the large diameter portion 24B). The elastic member 22 may also be provided so as not to cover (i.e., to expose) at least a part of the inner peripheral surface portion 29B on the peripheral surface 29 of the insert members 21A-21D. For example, as shown in FIG. 4, not only can the end edges (here, the front edges) of the inner circumferential surface portions 29B of the insert members 21A and 21C be exposed, but also the middle portions of the inner circumferential surface portions 29B in the front-to-rear direction can be exposed.

The elastic member 22 is formed, for example, from an elastomer exhibiting relatively high elasticity. The elastic member 22 may be formed by combining members made of two or more kinds of elastomers (for example, a plurality of different members are layered in the axial direction). The elastomers used in the elastic member 22 include thermosetting elastomers and thermoplastic elastomers. The thermosetting elastomers may include thermosetting resin-based elastomers (e.g., urethane rubber, silicone rubber, fluororubber, etc.) in addition to natural rubber and synthetic rubber. The thermoplastic elastomers may include known elastomers such as styrene-based, olefin-based, urethane-based, ester-based, PVC (polyvinyl chloride)-based, and amide-based elastomers.

When assembling the shaft coupling 1, the clamp hubs 3A, 3B and the element 4 are placed in the correct assembly position, and then, as shown in FIG. 4, two connecting bolts 41 (an example of a fastener) are fastened to the two screw holes 12 of the clamp hub 3A through the through holes 11 and bolt receiving holes 24 of the clamp hub 3B. As a result, the element 4 is fixed to the clamp hub 3A by the connecting bolts 41. At this time, the insert members 21A, 21C are fixed only to the clamp hub 3A of the pair of clamp hubs 3A, 3B.

At this time, the head 41A and washer 42 of each connecting bolt 41 are accommodated in the large diameter portion 24B of each bolt accommodating hole 24. The base end side (head 41A side) of the threaded portion 41B of each connecting bolt 41 is inserted into the small diameter portion 24A, and the tip side is screwed into the threaded hole 12 of the clamp hub 3A. The threaded portion 41B of each connecting bolt 41 is inserted into a plurality of annular distance pieces 45 interposed between the element 4 and the clamp hub 3A (more specifically, between the small diameter portion 24A of the bolt accommodating hole 24 and the threaded hole 12). A gap is secured between the clamp hub 3A and the element 4, which are connected to each other, by the distance pieces 45. In other words, the element 4 is arranged at a predetermined interval from the clamp hub 3A.

As in the case of the clamp hub 3A described above, the element 4 is fixed to the clamp hub 3B by the connecting bolt 41. At this time, the insert members 21B, 21D are fixed only to the clamp hub 3B of the pair of clamp hubs 3A, 3B. When the shaft fixing bolt 50 fitted into the fastening screw hole 19 is tightened in the clamp hubs 3A, 3B of the assembled shaft coupling 1, the split groove 14 shrinks (i.e., the periphery of the split groove 14 elastically deforms), and the shafts 2A, 2B are fixed to the shaft holes 10A, 10B, respectively. Also, when the shaft fixing bolt 50 is loosened in the clamp hubs 3A, 3B, the split groove 14 expands again (the split groove 14 restores), and the fixation of the shafts 2A, 2B to the shaft holes 10A, 10B is released.

Next, we will explain the manufacturing method of the shaft coupling 1.

In manufacturing the shaft coupling 1, first, the clamp hubs 3A, 3B are manufactured by cutting a metal material. In parallel with this, the insert members 21A-21D are manufactured by die casting. However, the insert members 21A-21D may also be formed by pressing or cutting. After that, the element 4 is insert molded. The manufacturing method of the clamp hubs 3A, 3B and the insert members 21A-21D is not particularly limited and may be changed as appropriate as necessary.

The element 4 is manufactured by insert molding (or vulcanization adhesion). In manufacturing the element 4, for example, an elastomer material is poured into a mold (not shown) in which the insert members 21A-21D are set, and they are molded together in the mold under specified pressure and temperature conditions (one example of a molding process). At this time, as described above, the insert members 21A-21D have a shape that tapers in a specified direction (i.e., one or the other axial side), so that they can be easily removed from the mold after insert molding to form the elastic member 22 around the insert members 21A-21D.

After that, once the clamp hubs 3A, 3B and element 4 are each completed, they are assembled into the shaft coupling 1 using the connecting bolts 41 as described above (one example of an assembly process).

With this shaft coupling 1 and its manufacturing method, there is no need to perform machining (e.g., forming the shaft holes 10A, 10B and 20) that requires high precision when the shaft coupling 1 is assembled, so a configuration in which an element 4 having an elastic member 22 is interposed between a pair of clamp hubs 3A, 3B can be easily realized without complicating the manufacturing process. In addition, this shaft coupling 1 has the advantage of increasing the degree of freedom in combining each clamp hub 3A, 3B with the element 4. Furthermore, since the element 4 can be completed independently of the clamp hubs 3A, 3B, there is also the advantage that the time required to manufacture the shaft coupling 1 can be shortened.

The present invention has been described above based on specific embodiments, but these embodiments are merely examples, and the present invention is not limited to these embodiments. Not all of the components of the shaft coupling and its manufacturing method shown in the above embodiments are necessarily essential, and at least those skilled in the art can select them as appropriate without departing from the scope of the present invention.

1: Shaft coupling 2A, 2B: Shaft 3A, 3B: Clamp hub 4: Element 5: Axis 10A, 10B: Shaft hole 11: Through hole 12: Screw hole 14: Split groove 15: Slit 17: Front surface 18: Outer circumferential surface 20: Shaft hole 21A-21D: Insert member 22: Elastic member 24: Bolt accommodating hole 24A: Small diameter portion 24B: Large diameter portion 27: Front surface 28: Rear surface 29: Circumferential surface 29A: Outer circumferential surface portion 29B: Inner circumferential surface portion 29C: Flat portion 30: Recess 41: Connecting bolt 41A: Head portion 41B: Threaded portion 42: Washer 45: Distance piece 50: Shaft fixing bolt

Claims (5)

A pair of metal hubs each having a shaft hole into which the two shafts are fitted,
an element disposed between the pair of hubs at a predetermined interval with respect to each of the hubs;
The element is
a plurality of metal insert members each having a pair of end faces arranged to face the hubs and a peripheral surface connected to the peripheral edges of the end faces, the insert members being fixed to the pair of hubs by fasteners;
an elastic member made of an elastomer provided so as to cover at least a portion of the peripheral surface of each of the insert members so as to be integral with the insert members;
the plurality of insert members include a first insert member fixed to only one of the pair of hubs and a second insert member fixed to only the other of the pair of hubs,
The element has an annular shape,
The plurality of insert members are disposed at equal intervals in the circumferential direction of the element,
Each insert member is provided to have a sector-shaped outer shape when viewed in the axial direction,
The elastic member is provided so as to cover the entire peripheral surface of each of the insert members . The shaft coupling according to claim 1 , wherein the pair of hubs and the element are provided to have the same outer diameter when viewed in the axial direction. 2. The shaft coupling according to claim 1 , wherein each of the hubs has a slot formed around the periphery of the shaft hole, and the shaft is detachably fixed by expanding and contracting the slot. A method for manufacturing a shaft coupling, comprising the steps of:
The shaft coupling comprises:
A pair of metal hubs each having a shaft hole into which the two shafts are fitted,
an element disposed between the pair of hubs at a predetermined interval with respect to each of the hubs;
The element is
a plurality of metal insert members each having a pair of end faces arranged to face the hubs and a peripheral surface connected to the peripheral edges of the end faces, the insert members being fixed to the pair of hubs by fasteners;
an elastic member made of an elastomer provided so as to cover at least a portion of the peripheral surface of each of the insert members so as to be integral with the insert members;
the plurality of insert members include a first insert member fixed to only one of the pair of hubs and a second insert member fixed to only the other of the pair of hubs,
a molding step of insert-molding the element so that the plurality of insert members and the elastic member are integrated;
and an assembly step of fixing the insert-molded elements to the pair of hubs with the fasteners. 5. The method for manufacturing a shaft coupling according to claim 4 , wherein each of the insert members is provided so as to be tapered toward one or the other side in the axial direction.

Images